The present invention relates to a viewfinder for a single lens reflex camera, in which the light from a photographing information indication, provided on a lens bodytube, is incident upon the incident light entry surface of a sub-prism provided on a front non-reflecting surface of a pentagonal roof prism, and is reflected by a final reflecting surface of the sub-prism to direct the light through the pentagonal prism, so that an image of the photographing information indication is provided within the field of vision of the viewfinder.
This kind of view finder has already been disclosed in the specification of U.S. Pat. No. 3,094,911. However, the viewfinder disclosed in U.S. Pat. No. 3,094,911 has a sub-prism, provided at front non-reflecting surface of a pentagonal roof prism which conspicuously protrudes, presenting an awkward appearance.
Also, since interchangeable objective lenses of large lens diameter are used recently, the sub-prism has become an obstacle for a lens barrel. To avoid the same, the sub-prism may be fixedly provided at the upper portion of the non-reflecting surface, but, in this case, there will result such a shortcoming that the image of the indication formed at greatly distant position from a focussing screen within the finder field of vision, making the image of the indication hard to be viewed.